Synchronous hydraulic multi-stage oil cylinder

Abstract

The utility model relates to a synchronous hydraulic multi-stage oil cylinder, and relates to the technical field of hydraulic oil cylinders, the synchronous hydraulic multi-stage oil cylinder comprises an outer cylinder barrel, a piston rod, a penultimate-stage cylinder barrel, a last-stage cylinder barrel and at least one middle cylinder barrel, the wall of the middle cylinder barrel is in threaded connection with a middle piston, the penultimate-stage cylinder barrel is in threaded connection with a penultimate-stage piston, and the last-stage cylinder barrel is in threaded connection with a last-stage piston. An inner piston is arranged at the end, close to the cylinder bottom, of the piston rod, the middle piston, the penultimate-stage piston and the last-stage piston are in threaded connection with one-way valves, the middle piston, the penultimate-stage piston and the last-stage piston are each provided with an oil passing channel, and the oil passing channels communicate with the one-way valves. The ends, away from the cylinder bottom, of the middle piston, the penultimate-stage piston and the last-stage piston are in threaded connection with second ejector rods, the first ejector rods and the second ejector rods are used for blocking the one-way valves, and the end, close to the cylinder bottom, of the outer cylinder barrel communicates with an oil pipe. The oil cylinder has the effects that the multi-stage piston rods synchronously stretch out and retract, and the use efficiency and stability of the oil cylinder are improved.

Description

Technical Field

[0001] This application relates to the technical field of hydraulic cylinders, and in particular to a synchronous hydraulic multi-stage cylinder. Background Art

[0002] Hydraulic multi-stage cylinders have been widely used in construction machinery, agricultural machinery, and automated production lines because they can achieve a longer stroke within a limited space, improving space utilization efficiency and meeting various application requirements. With the continuous development of technology, the requirements for load capacity, stroke control, and structural compactness of multi-stage cylinders have also been increasing, promoting the progress of cylinder technology. Corresponding improved designs emerge in an endless stream, further enhancing the overall performance.

[0003] For different application requirements of traditional multi-stage cylinders, common solutions in the market mainly include achieving the movement of the piston rod by the sequential extension method between stages, that is, realizing multi-stage strokes by controlling the extension and retraction of each piston rod step by step; another method is to use an independent control device or introduce additional pipelines to control the movement of the piston rod in levels; there is also a common way to design a connected oil passage inside the cylinder combined with a step-by-step throttling device to orderly control the movement process of each stage of the piston rod inside the cylinder. In addition, in order to ensure the stability and smoothness of the piston rod throughout the stroke, some technical solutions also add guiding and supporting elements to maintain good straightness and structural stability.

[0004] Although the above solutions can meet the basic usage requirements of multi-stage cylinders to a certain extent, they generally have a problem, that is, the step-by-step control mode results in a longer time required for the cylinder to fully extend or retract, unable to meet the requirements of high-efficiency operation. In addition, when changing levels, the mass difference between the piston rods often causes a sense of jerk, making the operation of the entire system not smooth enough. These problems are restricting the performance of multi-stage cylinders in practical applications. Summary of the Utility Model

[0005] In order to achieve the effect of synchronous extension and retraction of multi-stage piston rods and improve the usage efficiency and stability of the cylinder, this application provides a synchronous hydraulic multi-stage cylinder.

[0006] This application provides a synchronous hydraulic multi-stage cylinder, adopting the following technical solutions:

[0007] A synchronous hydraulic multi-stage cylinder, comprising an outer cylinder barrel, a piston rod, a second last-stage cylinder barrel, a last-stage cylinder barrel and at least one intermediate cylinder barrel. The outer cylinder barrel, the intermediate cylinder barrel, the second last-stage cylinder barrel, the last-stage cylinder barrel and the piston rod are nested in sequence from outside to inside. One end of the outer cylinder barrel is provided with a cylinder bottom. On the outer side wall of one end of the intermediate cylinder barrel close to the cylinder bottom, an intermediate piston is threadedly connected. On the outer side wall of one end of the second last-stage cylinder barrel close to the cylinder bottom, a second last-stage piston is threadedly connected. On the outer side wall of one end of the last-stage cylinder barrel close to the cylinder bottom, a last-stage piston is threadedly connected. One end of the piston rod close to the cylinder bottom is provided with an inner piston. The end of the inner piston far from the cylinder bottom is inserted into the piston rod and is threadedly connected with the piston rod. On the inner walls of the ends of the intermediate piston, the second last-stage piston and the last-stage piston close to the cylinder bottom, one-way valves are threadedly connected. The intermediate piston, the second last-stage piston and the last-stage piston are all provided with oil passing channels communicating with the outer cylinder barrel or the intermediate cylinder barrel or the second last-stage cylinder barrel or the last-stage cylinder barrel. One end of the oil passing channel close to the cylinder bottom is communicated with the one-way valve. The cylinder bottom is provided with a first ejector rod. One ends of the intermediate piston, the second last-stage piston and the last-stage piston far from the cylinder bottom are all threadedly connected with a second ejector rod. One ends of both the first ejector rod and the second ejector rod are inserted into one end of the one-way valve close to the cylinder bottom. The first ejector rod and the second ejector rod are used to block the one-way valve. Chamfers are provided at the ends of the intermediate piston, the second last-stage piston and the last-stage piston close to the cylinder bottom. The diameter of the chamfers gradually decreases towards the direction close to the cylinder bottom. One end of the outer cylinder barrel close to the cylinder bottom is communicated with an oil pipe. The communication port of the oil pipe with the outer cylinder body is located between the end with the largest chamfer diameter and the cylinder bottom.

[0008] By adopting the above technical solution, one-way valves are arranged at the piston parts of each stage of cylinder barrel. At the same time, a first ejector rod and a second ejector rod are arranged to control the opening and closing of the one-way valves. Each stage of piston divides each stage of cylinder barrel into a rod chamber and a non-rod chamber. Among them, the stress area of the outermost intermediate cylinder barrel is the entire cross-sectional area of the inner cavity of the outer cylinder barrel. With a large stress area, the primary thrust of the hydraulic cylinder is maximized, and the outermost intermediate cylinder barrel and the inner cylinder barrel and the piston rod inside it are pushed out together. After reaching the position, the oil pressure gradually rises and opens the one-way valve arranged on the outermost intermediate cylinder barrel. The oil enters the non-rod chamber of the next stage, and gradually pushes out each stage of cylinder barrel in sequence, and finally pushes out the piston rod. The effect of synchronous extension and retraction of the multi-stage piston rod is achieved, and the use efficiency and stability of the cylinder are improved. Among them, the stress areas of each non-rod chamber gradually decrease, and the thrust gradually decreases. Moreover, by setting the lengths of the first ejector rod and the second ejector rod inserted into the one-way valve, the extension thrust of each stage is controllable and adjustable, which is suitable for complex working conditions of driving different-level loads.

[0009] Optionally, a first guide sleeve is threadedly connected to the inner wall of one end of the outer cylinder barrel far from the cylinder bottom. A second guide sleeve is threadedly connected to the inner wall of one end of the intermediate cylinder barrel far from the cylinder bottom. A third guide sleeve is threadedly connected to the inner wall of one end of the second last-stage cylinder barrel far from the cylinder bottom. A fourth guide sleeve is threadedly connected to the outer wall of one end of the last-stage cylinder barrel far from the cylinder bottom. A flange plate is arranged on the outside of the fourth guide sleeve.

[0010] By adopting the above technical solution, the provision of the first guide sleeve, the second guide sleeve, the third guide sleeve and the fourth guide sleeve enables the guide and support of the cylinder barrels and the piston rod at all levels in the multi-stage oil cylinder, improves the movement smoothness and structural stability, and can prevent the cylinder barrels and the piston rod at all levels from disengaging from the hydraulic cylinder. Moreover, the provision of the flange plate facilitates the fixed installation of the last-stage cylinder barrel, further enhancing the reliability of the entire system.

[0011] Optionally, two first support rings are sleeved on the outer side wall of the inner piston. The inner wall of the first support ring is embedded in the outer side wall of the inner piston, and the outer wall of the first support ring abuts against the inner wall of the last-stage cylinder barrel.

[0012] By adopting the above technical solution, the two first support rings sleeved on the outer side wall of the inner piston can enhance the stability between the inner piston and the last-stage cylinder barrel, reduce the swaying of the piston rod during movement, and thus improve the overall smoothness and reliability of the multi-stage oil cylinder.

[0013] Optionally, a plurality of through grooves are circumferentially formed on the outer wall of the first support ring, and the extending direction of the through grooves is the same as the axial direction of the inner piston.

[0014] By adopting the above technical solution, the plurality of through grooves circumferentially formed on the outer wall of the first support ring can provide a better lubricating oil flow channel during the movement of the piston, effectively reduce the movement resistance, and improve the movement smoothness of the entire multi-stage oil cylinder.

[0015] Optionally, a dust ring and a shaft seal are embedded in the inner wall of the first guide sleeve, the second guide sleeve, the third guide sleeve and the fourth guide sleeve at the end away from the cylinder bottom, and the dust ring is located on the side of the shaft seal away from the cylinder bottom.

[0016] By adopting the above technical solution, the dust ring and the shaft seal effectively prevent external dust and impurities from entering the inside of the oil cylinder, and at the same time ensure the sealing performance during the movement of the piston rod, improving the service life and reliability of the oil cylinder.

[0017] Optionally, two second support rings are embedded in the inner wall of the second guide sleeve on the side of the oil seal close to the cylinder bottom, the inner wall of the second support ring abuts against the outer wall of the second last-stage cylinder barrel, one third support ring is embedded in the inner wall of the third guide sleeve on the side of the oil seal close to the cylinder bottom, the inner wall of the third support ring abuts against the outer wall of the last-stage cylinder barrel, and two fourth support rings are respectively embedded in the inner walls at both ends of the fourth guide sleeve. Both of the two fourth support rings are located on the side of the dust ring in the fourth guide sleeve close to the cylinder bottom, and the inner wall of the fourth support ring abuts against the outer wall of the piston rod.

[0018] By adopting the above technical solution, the second support ring can effectively support the sub-final stage cylinder barrel, enhancing the guiding and stability of the sub-final stage cylinder barrel; the third support ring can provide stable guiding for the final stage cylinder barrel; the fourth support ring can provide good guiding and supporting functions during the movement of the piston rod, enhancing the stability of the piston rod. The setting of these support rings makes the cylinder barrels and the piston rod of each stage more stable during the extension and retraction processes, effectively reducing jerks and improving the stability and reliability of the entire multi-stage oil cylinder.

[0019] Optionally, a spacer sleeve is provided between the first guide sleeve and the intermediate piston, between the second guide sleeve and the sub-final stage piston, and between the third guide sleeve and the final stage piston. The spacer sleeves are respectively sleeved on the outer side walls of the intermediate cylinder barrel, the sub-final stage cylinder barrel, and the final stage cylinder barrel.

[0020] By adopting the above technical solution, the spacer sleeve can ensure the shortest lengths of the intermediate cylinder barrel, the sub-final stage cylinder barrel, and the final stage cylinder barrel in the cylinder body, thereby improving the stability and reliability of the entire oil cylinder structure.

[0021] Optionally, hole-type combined seals are embedded on the outer walls of the intermediate piston, the sub-final stage piston, and the final stage piston, and the inner walls of the outer cylinder barrel, the intermediate cylinder barrel, and the sub-final stage cylinder barrel are respectively in abutment with the outer side walls of the hole-type combined seals.

[0022] By adopting the above technical solution, the hole-type combined seals can effectively prevent hydraulic oil leakage, ensure the sealing performance during the synchronous movement of each piston, and thus improve the overall working stability and reliability of the multi-stage oil cylinder.

[0023] In summary, the present application includes at least one of the following beneficial technical effects:

[0024] 1. One-way valves are provided at the piston parts of the cylinder barrels of each stage. At the same time, a first ejector rod and a second ejector rod are provided to control the opening and closing of the one-way valves. Each piston divides each cylinder barrel into a rod chamber and a rodless chamber. Among them, the force-bearing area of the outermost intermediate cylinder barrel is the entire cross-sectional area of the inner cavity of the outer cylinder barrel. With a large force-bearing area, the primary thrust of the hydraulic cylinder is maximized, pushing the outermost intermediate cylinder barrel and the internal cylinder barrel and the piston rod inside it to extend together. After reaching the extended position, the oil pressure gradually increases and opens the one-way valve provided on the outermost intermediate cylinder barrel. The oil enters the rodless chamber of the next stage, gradually pushing the cylinder barrels of each stage to extend in turn, and finally pushing the piston rod to extend. The effect of synchronous extension and retraction of the multi-stage piston rod is achieved, improving the use efficiency and stability of the oil cylinder. Among them, the force-bearing areas of the rodless chambers of each stage decrease in turn, and the thrust gradually decreases. Moreover, by setting the lengths of the first ejector rod and the second ejector rod inserted into the one-way valve, the extension thrust of each stage is controllable and adjustable, suitable for complex working conditions of driving different-level loads.

[0025] 2. The provision of the first guide sleeve, the second guide sleeve, the third guide sleeve and the fourth guide sleeve enables the guide and support of the cylinder barrels and piston rods at all levels in the multi-stage oil cylinder, improving the motion smoothness and structural stability, preventing the cylinder barrels and piston rods at all levels from disengaging from the hydraulic cylinder, and the provision of the flange plate facilitates the fixed installation of the last-stage cylinder barrel, further enhancing the reliability of the entire system;

[0026] 3. The two first support rings sleeved on the outer side wall of the inner piston can enhance the stability between the inner piston and the last-stage cylinder barrel, reduce the swaying during the movement of the piston rod, and thus improve the overall smoothness and reliability of the multi-stage oil cylinder. Description of the Drawings

[0027] Figure 1 is a schematic cross-sectional view of the overall structure of a synchronous hydraulic multi-stage oil cylinder.

[0028] Figure 2 is a schematic cross-sectional view of the outer cylinder barrel.

[0029] Figure 3 is a schematic cross-sectional view of the intermediate cylinder barrel.

[0030] Figure 4 is a schematic cross-sectional view of the second-to-last stage cylinder barrel.

[0031] Figure 5 is a schematic cross-sectional view of the last-stage cylinder barrel.

[0032] Figure 6 is a schematic cross-sectional view of the piston rod cylinder barrel.

[0033] Figure 7 is a schematic structural view of the first support ring.

[0034] Description of the Reference Numerals: 1. Outer cylinder barrel; 11. Cylinder bottom; 111. First ejector rod; 12. First guide sleeve; 13. Dust seal; 14. Shaft seal; 2. Intermediate cylinder barrel; 21. Intermediate piston; 211. Second ejector rod; 22. Second guide sleeve; 23. Second support ring; 24. Hole combination seal; 3. Second-to-last stage cylinder barrel; 31. Second-to-last stage piston; 32. Third guide sleeve; 33. Third support ring; 4. Last-stage cylinder barrel; 41. Last-stage piston; 42. Fourth guide sleeve; 421. Flange plate; 43. Fourth support ring; 5. Piston rod; 51. Inner piston; 52. First support ring; 53. Through groove; 6. Check valve; 7. Oil pipe; 8. Oil passage; 9. Spacer sleeve. Detailed Embodiments

[0035] The following further describes the present application in detail with reference to all the drawings.

[0036] The embodiments of the present application disclose a synchronous hydraulic multi-stage oil cylinder.

[0037] Refer toFigure 1 , a synchronous hydraulic multi-stage cylinder, comprising an outer cylinder barrel 1, a piston rod 5, a second last-stage cylinder barrel 3, a last-stage cylinder barrel 4 and at least one intermediate cylinder barrel 2. The outer cylinder barrel 1, the intermediate cylinder barrel 2, the second last-stage cylinder barrel 3, the last-stage cylinder barrel 4 and the piston rod 5 are nested in sequence from outside to inside.

[0038] Refer to Figure 1 , one end of the piston rod 5 close to the cylinder bottom 11 is provided with an inner piston 51. One end of the inner piston 51 away from the cylinder bottom 11 is inserted into the piston rod 5 and is threadedly connected with the piston rod 5. The outer side wall of the intermediate cylinder barrel 2 at one end close to the cylinder bottom 11 is threadedly connected with an intermediate piston 21. The outer side wall of the second last-stage cylinder barrel 3 at one end close to the cylinder bottom 11 is threadedly connected with a second last-stage piston 31. The outer side wall of the last-stage cylinder barrel 4 at one end close to the cylinder bottom 11 is threadedly connected with a last-stage piston 41.

[0039] Refer to Figure 1 , check valve 6 is threadedly connected to the inner walls of one ends of the intermediate piston 21, the second last-stage piston 31 and the last-stage piston 41 close to the cylinder bottom 11. The flow direction of the check valve 6 is from the oil pipe 7 to the direction away from the cylinder bottom 11. The intermediate piston 21, the second last-stage piston 31 and the last-stage piston 41 are all provided with oil passage 8 communicating with the outer cylinder barrel 1 or the intermediate cylinder barrel 2 or the second last-stage cylinder barrel 3 or the last-stage cylinder barrel 4. One end of the oil passage 8 close to the cylinder bottom 11 is communicated with the check valve 6. Second ejector rods 211 are threadedly connected to the other ends of the intermediate piston 21, the second last-stage piston 31 and the last-stage piston 41 away from the cylinder bottom 11. One ends of the first ejector rod 111 and the second ejector rods 211 are inserted into one ends of the check valve 6 close to the cylinder bottom 11. The first ejector rod 111 and the second ejector rods 211 are used to block the check valve 6.

[0040] Refer to Figure 1 , hole combination seals 24 are embedded on the outer walls of the intermediate piston 21, the second last-stage piston 31 and the last-stage piston 41. The inner walls of the outer cylinder barrel 1, the intermediate cylinder barrel 2 and the second last-stage cylinder barrel 3 are in contact with the outer side walls of the hole combination seals 24 in one-to-one correspondence. The hole combination seals 24 can effectively prevent hydraulic oil leakage, ensure the sealing performance during the synchronous movement of each piston, and thus improve the overall working stability and reliability of the multi-stage cylinder

[0041] Refer to Figure 1 , chamfers are provided at one ends of the intermediate piston 21, the second last-stage piston 31 and the last-stage piston 41 close to the cylinder bottom 11. The diameter of the chamfer gradually decreases towards the direction close to the cylinder bottom 11. The communication port between the oil pipe 7 and the outer cylinder body is located between the end with the largest chamfer diameter and the cylinder bottom 11.

[0042] Refer to Figure 2, one end of the outer cylinder barrel 1 is provided with a cylinder bottom 11, a first ejector rod 111 is inserted into the cylinder bottom 11, and an oil pipe 7 is communicated with one end of the outer cylinder barrel 1 close to the cylinder bottom 11. The oil pipe 7 is used for injecting oil into or pumping oil out of the outer cylinder barrel 1. The inner wall of the outer cylinder barrel 1 at the end far from the cylinder bottom 11 is threadedly connected with a first guide sleeve 12. A dust-proof ring 13 and a shaft seal 14 are embedded in the inner wall of the first guide sleeve 12 at the end far from the cylinder bottom 11. The inner walls of the dust-proof ring 13 and the shaft seal 14 are in contact with the middle cylinder barrel 2. The dust-proof ring 13 is located on the side of the shaft seal 14 far from the cylinder bottom 11. The setting of the first guide sleeve 12 enables the middle cylinder barrel 2 to obtain guiding support, improves the motion stability and structural stability, and can prevent the middle cylinder barrel 2 from disengaging from the hydraulic cylinder.

[0043] Referring to Figure 3 , a second guide sleeve 22 is threadedly connected to the inner wall of the middle cylinder barrel 2 at the end far from the cylinder bottom 11. A dust-proof ring 13, a shaft seal 14 and two second support rings 23 are sequentially embedded in the inner wall of the second guide sleeve 22 from the end far from the cylinder bottom 11 to the end close to the cylinder bottom 11. The inner walls of the dust-proof ring 13, the shaft seal 14 and the second support ring 23 are in contact with the outer wall of the sub-final stage cylinder barrel 3. The settings of the second guide sleeve 22 and the second support ring 23 enable the sub-final stage cylinder barrel 3 to obtain guiding support, improve the motion stability and structural stability, and the second guide sleeve 22 can prevent the sub-final stage cylinder barrel 3 from disengaging from the hydraulic cylinder.

[0044] Referring to Figure 4 , a third guide sleeve 32 is threadedly connected to the inner wall of the sub-final stage cylinder barrel 3 at the end far from the cylinder bottom 11. A dust-proof ring 13, a shaft seal 14 and a third support ring 33 are sequentially embedded in the inner wall of the third guide sleeve 32 from the end far from the cylinder bottom 11 to the end close to the cylinder bottom 11. The inner walls of the dust-proof ring 13, the shaft seal 14 and the third support ring 33 are in contact with the outer wall of the final stage cylinder barrel 4. The settings of the third guide sleeve 32 and the third support ring 33 enable the final stage cylinder barrel 4 to obtain guiding support, improve the motion stability and structural stability, and the second guide sleeve 22 can prevent the final stage cylinder barrel 4 from disengaging from the hydraulic cylinder.

[0045] Referring to Figure 5 , a fourth guide sleeve 42 is threadedly connected to the outer wall of the final stage cylinder barrel 4 at the end far from the cylinder bottom 11. A flange plate 421 is arranged on the outside of the fourth guide sleeve 42. A dust-proof ring 13, a shaft seal 14 and two fourth support rings 43 are embedded in the inner wall of the fourth guide sleeve 42 at the end far from the cylinder bottom 11. The two fourth support rings 43 are respectively located at both ends of the oil seal and on the side of the dust-proof ring 13 close to the cylinder bottom 11. The inner walls of the dust-proof ring 13, the shaft seal 14 and the fourth support ring 43 are in contact with the outer wall of the piston rod 5. The settings of the fourth guide sleeve 42 and the fourth support ring 43 enable the piston rod 5 to obtain guiding support, improve the motion stability and structural stability, and the second guide sleeve 22 can prevent the piston rod 5 from disengaging from the hydraulic cylinder.

[0046] Reference Figure 6 and Figure 7 As shown in Figure 6 and Figure 7 , two first support rings 52 are sleeved on the outer side wall of the inner piston 51. The inner wall of the first support ring 52 is embedded in the outer side wall of the inner piston 51, and the outer wall of the first support ring 52 abuts against the inner wall of the last-stage cylinder barrel 4. A plurality of through grooves 53 are formed in the outer wall of the first support ring 52 in the circumferential direction, and the extending direction of the through grooves 53 is the same as the axial direction of the inner piston 51. The first support ring 52 can enhance the stability between the inner piston 51 and the last-stage cylinder barrel 4, reduce the swaying during the movement of the piston rod 5, and the through grooves 53 can provide a better lubricating oil flow channel during the piston movement, effectively reducing the movement resistance, thereby improving the overall smoothness and reliability of the multi-stage oil cylinder.

[0047] The dust ring 13 and the shaft seal 14 effectively prevent external dust and impurities from entering the inside of the oil cylinder, and at the same time ensure the sealing performance during the movement of the piston rod 5, improving the service life and reliability of the oil cylinder. The first support ring 52, the second support ring 23, the third support ring 33 and the fourth support ring 43 can all be provided with openings for convenient disassembly.

[0048] Reference Figure 2 、 Figure 3 and Figure 4 As shown in Figure 2 , Figure 3 and Figure 4 , spacer sleeves 9 are provided between the first guide sleeve 12 and the intermediate piston 21, between the second guide sleeve 22 and the sub-last-stage piston 31, and between the third guide sleeve 32 and the last-stage piston 41. The spacer sleeves 9 are respectively sleeved on the outer side walls of the intermediate cylinder barrel 2, the sub-last-stage cylinder barrel 3 and the last-stage cylinder barrel 4. When each stage of the cylinder barrel extends to the longest, the end of the spacer sleeve 9 away from the cylinder bottom 11 abuts against the corresponding guide sleeve of each stage of the cylinder barrel. The spacer sleeve 9 can ensure the shortest length of the intermediate cylinder barrel 2, the sub-last-stage cylinder barrel 3 and the last-stage cylinder barrel 4 in the cylinder body, thereby improving the stability and reliability of the entire oil cylinder structure.

[0049] The implementation principle of a synchronous hydraulic multi-stage cylinder in an embodiment of this application is as follows: One-way valves 6 are provided at the piston parts of each stage of cylinder barrels. At the same time, a first ejector rod 111 and a second ejector rod 211 are provided to control the opening and closing of the one-way valves 6. Each stage of piston divides each stage of cylinder barrel into a rod chamber and a rodless chamber. Among them, the stress area of the outermost intermediate cylinder barrel 2 is the entire cross-sectional area of the inner cavity of the outer cylinder barrel 1. With a large stress area, the primary thrust of the hydraulic cylinder is maximized, pushing the outermost intermediate cylinder barrel 2 and the inner cylinder barrels and the piston rod 5 inside it to extend together. After the extension is in place, the oil pressure gradually rises to open the one-way valve 6 provided on the outermost intermediate cylinder barrel 2, and the oil enters the rodless chamber of the next stage, gradually pushing each stage of cylinder barrel to extend in turn, and finally pushing the piston rod 5 to extend. The effect of synchronous extension and retraction of the multi-stage piston rod 5 is achieved, improving the use efficiency and stability of the cylinder. Among them, the stress areas of each rodless chamber decrease in turn, and the thrust gradually decreases. Moreover, by setting the lengths of the first ejector rod 111 and the second ejector rod 211 inserted into the one-way valve 6, the extension thrust of each stage is controllable and adjustable, suitable for complex working conditions of driving loads of different levels.

[0050] The above are all preferred embodiments of this application. Without restricting the protection scope of this application accordingly, therefore: All equivalent changes made according to the structure, shape, and principle of this application shall be covered within the protection scope of this application.

Claims

1. A synchronous hydraulic multi-stage cylinder, comprising an outer cylinder barrel (1), a piston rod (5), a second-to-last stage cylinder barrel (3), a last stage cylinder barrel (4) and at least one intermediate cylinder barrel (2). The outer cylinder barrel (1), the intermediate cylinder barrel (2), the second-to-last stage cylinder barrel (3), the last stage cylinder barrel (4) and the piston rod (5) are nested in sequence from outside to inside. One end of the outer cylinder barrel (1) is provided with a cylinder bottom (11), and it is characterized in that: On the outer side wall of the middle cylinder barrel (2) at one end close to the cylinder bottom (11), a middle piston (21) is threadedly connected. On the outer side wall of the sub-final stage cylinder barrel (3) at one end close to the cylinder bottom (11), a sub-final stage piston (31) is threadedly connected. On the outer side wall of the final stage cylinder barrel (4) at one end close to the cylinder bottom (11), a final stage piston (41) is threadedly connected. At one end of the piston rod (5) close to the cylinder bottom (11), an inner piston (51) is provided. One end of the inner piston (51) away from the cylinder bottom (11) is inserted into the piston rod (5) and is threadedly connected to the piston rod (5). On the inner walls of the ends of the middle piston (21), the sub-final stage piston (31), and the final stage piston (41) close to the cylinder bottom (11), one-way valves (6) are threadedly connected. The middle piston (21), the sub-final stage piston (31), and the final stage piston (41) are all provided with oil passageways (8) communicating with the outer cylinder barrel (1), the middle cylinder barrel (2), the sub-final stage cylinder barrel (3), or the final stage cylinder barrel (4). One end of the oil passageway (8) close to the cylinder bottom (11) communicates with the one-way valve (6). The cylinder bottom (11) is provided with a first ejector rod (111). At the ends of the middle piston (21), the sub-final stage piston (31), and the final stage piston (41) away from the cylinder bottom (11), second ejector rods (211) are threadedly connected. One ends of both the first ejector rod (111) and the second ejector rod (211) are inserted into one end of the one-way valve (6) close to the cylinder bottom (11). The first ejector rod (111) and the second ejector rod (211) are used to block the one-way valve (6). At the ends of the middle piston (21), the sub-final stage piston (31), and the final stage piston (41) close to the cylinder bottom (11), chamfers are provided. The diameter of the chamfers gradually decreases in the direction close to the cylinder bottom (11). One end of the outer cylinder barrel (1) close to the cylinder bottom (11) is communicated with an oil pipe (7). The communication port of the oil pipe (7) with the outer cylinder body is located between the end with the largest chamfer diameter and the cylinder bottom (11).

2. A synchronous hydraulic multi-stage cylinder according to claim 1, characterized in that: On the inner wall of the outer cylinder barrel (1) at one end away from the cylinder bottom (11), a first guide sleeve (12) is threadedly connected. On the inner wall of the middle cylinder barrel (2) at one end away from the cylinder bottom (11), a second guide sleeve (22) is threadedly connected. On the inner wall of the sub-final stage cylinder barrel (3) at one end away from the cylinder bottom (11), a third guide sleeve (32) is threadedly connected. On the outer wall of the final stage cylinder barrel (4) at one end away from the cylinder bottom (11), a fourth guide sleeve (42) is threadedly connected. A flange plate (421) is provided on the outside of the fourth guide sleeve (42).

3. The synchronous hydraulic multi-stage oil cylinder according to claim 1, characterized in that: Two first support rings (52) are sleeved on the outer side wall of the inner piston (51). The inner walls of the first support rings (52) are embedded in the outer side wall of the inner piston (51). The outer walls of the first support rings (52) are in contact with the inner wall of the final stage cylinder barrel (4).

4. A synchronous hydraulic multi-stage cylinder according to claim 3, characterized in that: A plurality of through grooves (53) are circumferentially formed on the outer wall of the first support ring (52). The extending direction of the through grooves (53) is the same as the axial direction of the inner piston (51).

5. A synchronous hydraulic multi-stage cylinder according to claim 2, characterized in that: The inner walls of the first guide sleeve (12), the second guide sleeve (22), the third guide sleeve (32) and the fourth guide sleeve (42) are all embedded with a dust ring (13) and a shaft seal (14) at the end away from the bottom of the cylinder (11). The dust ring (13) is located on the side of the shaft seal (14) away from the bottom of the cylinder (11).

6. A synchronous hydraulic multi-stage cylinder according to claim 2, characterized in that: Two second support rings (23) are embedded in the inner wall of the second guide sleeve (22) on the side of the oil seal close to the bottom of the cylinder (11). The inner walls of the second support rings (23) are in contact with the outer wall of the sub-final stage cylinder barrel (3). One third support ring (33) is embedded in the inner wall of the third guide sleeve (32) on the side of the oil seal close to the bottom of the cylinder (11). The inner wall of the third support ring (33) is in contact with the outer wall of the final stage cylinder barrel (4). Two fourth support rings (43) are respectively embedded in the inner walls at both ends of the fourth guide sleeve (42). Both of the two fourth support rings (43) are located on the side of the dust ring (13) in the fourth guide sleeve (42) close to the bottom of the cylinder (11). The inner walls of the fourth support rings (43) are in contact with the outer wall of the piston rod (5).

7. A synchronous hydraulic multi-stage cylinder according to claim 2, characterized in that: Spacer sleeves (9) are provided between the first guide sleeve (12) and the intermediate piston (21), between the second guide sleeve (22) and the sub-final stage piston (31), and between the third guide sleeve (32) and the final stage piston (41). The spacer sleeves (9) are respectively sleeved on the outer side walls of the intermediate cylinder barrel (2), the sub-final stage cylinder barrel (3) and the final stage cylinder barrel (4).

8. A synchronous hydraulic multi-stage cylinder according to claim 1, characterized in that: Orifice packings (24) are embedded in the outer walls of the intermediate piston (21), the sub-final stage piston (31) and the final stage piston (41). The inner walls of the outer cylinder barrel (1), the intermediate cylinder barrel (2) and the sub-final stage cylinder barrel (3) are respectively in contact with the outer side walls of the orifice packings (24).

Images